Eigenschaften von ultradünnen Polymerfilmen: Wie entsteht dreidimensionales Verhalten?

点击翻译按钮获取中文摘要

Structural and dynamical properties of ultrathin polymer films will be analyzed by computer simulations. The planned simulations consider, on the one hand, strictly two-dimensional systems, where all monomers of the polymer chains are attached to a flat substrate, and on the other hand, ultrathin films, where small excursions of monomers into the third dimension are allowed. For dense systems and long chains, the latter choice leads to strong entanglements between the chains, as in three dimensions. Polymers that can move over each other should thus hamper themselves in their motion much more than strictly twodimensional systems. A recent theory, which provides quantitative predictions about these modifications, will be tested carefully via the computer simulations. Since this theory also suggests that the well-established "reptation model" of Edwards, Doi and de Gennes might not be the correct description of the polymer relaxation in the asymptotic limit of large chains, as commonly assumed, the results of the planned project could present a very important contribution to a fundamental problem in polymer physics.